Sen Zhou

Preparation, characterization, and Ce(III) adsorption performance of poly (allylamine)/silica composite

AbstractIn the present work, an organic–inorganic hybrid composite (poly(allylamine)/silica) was facilely prepared through grafting poly(allylamine) onto the modified silica. Surface property, morphology, and texture parameters of the composite were characterized by infrared spectroscopy (FTIR), scanning electron microscopy, and N2 adsorption/desorption measurements, respectively. Then, the adsorptive property of this composite for recovery of Ce(III) was investigated systematically. Batch tests were performed under a range of conditions to examine the effects of contact time, adsorbent amount, initial Ce(III) concentration, and solution pH. At optimal experimental conditions, the maximum adsorption capacity of Ce(III) was up to 111.8 mg g−1. Full kinetic and thermodynamic investigations as well as isotherm analysis were also undertaken. It was found that the adsorption kinetics could be well fitted by the pseudo-second-order model, whereas the Freundlich model provided the better description for the equi...

Fabrication of sponge biomass adsorbent through UV-induced surface-initiated polymerization for the adsorption of Ce(III) from wastewater

The recovery of rare earth ions from industrial wastewater has aroused wide concern in recent years. In present work, we synthesized a novel three-dimensional adsorbent (denoted as LF-AA) by grafting loofah fiber with acrylic acid via ultraviolet radiation. The LF-AA was washed by boiling water and subjected to soxhlet extraction with acetone and then fully characterized by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and scanning electron microscopy (SEM). Rare earth ion (Ce(III)) was selected as a model to validate its adsorption property. The saturation adsorption capacity for Ce(III) reaches 527.5 mg/g. Not only was this material highly efficient at adsorbing Ce(III) from aqueous solutions, it also proved to have ideal performance in regeneration; the total adsorption capacity of LF-AA for Ce(III) after six successive cycles decreased only 6.40% compared with the initial capacity of LF-AA. More importantly, the LF-AA can be easily separated from aqueous solutions because of its three-dimensional sponge natural structure. This study provides a new insight into the fabrication of biomass adsorbent and demonstrated that the LF-AA can be used as excellent adsorbent for the recovery of rare earth ions from wastewater.

Polyacrylic acid grafted silica fume as an excellent adsorbent for dysprosium(III) removal from industrial wastewater

In the development of industrial life, an enormous amount of silica fume (SF) has been accumulated and cannot be reused properly, and a large quantity of rare-earth elements in industrial wastewater has been inappropriately discharged, both of which pose a threat to human health and the environment. By using UV photocatalytic grafting technology, a polymer brush grafted from modified SF, which can be used as a high efficiency adsorbent, can solve both problems at the same time. Specifically, SF was firstly silanol-functionalized by γ-methacryloxypropyltrimethoxysilane (KH570), then grafted with polyacrylic acid brushes by UV photocatalytic grafting to finally obtain the adsorbent. Under optimal conditions, adsorption capacity of the adsorbent for dysprosium(III) (Dy3+) could reach 278.49 mg/g. It took 1 min for the adsorbent to reach adsorbing equilibrium at a relatively low concentration of Dy3+ (40 mg/L), and only 3 min at a medium and high concentration (130 mg/L and 200 mg/L). After six adsorption-desorption cycles, the adsorbent still possessed high adsorption capacity for Dy3+ (251.20 mg/g). The adsorption behavior of the adsorbent fit the Langmuir isotherm model (R2 > 0.97) and pseudo-second-order kinetic model (R2 > 0.98) well. The functional group of carboxylate anion, -COO-, played a central role during the adsorption process, which was verified by Fourier transform infrared and X-ray photoelectron spectroscopy analyses.

Preparation of Monodisperse Functional Polystyrene/Silica Microsphere Composite via Suspension Polymerization Method

The monodisperse functional Polystyrene/Silica (PS/silica) microsphere has been successfully prepared via suspension polymerization followed by the modified silica composite phenylethylene method. The FTIR, SEM, EDS and BEI were used to characterize the structure and composition of monodisperse functional PS/Silica microspheres. The results indicated that the dosage of silica modifier affect the compatibility of the modified silica and phenyl ethylene. The several modified silica would synergistically impact on the morphology and performance of products corresponding to distinguish formation mechanisms. The thermal stability and compressive strength performance had been improved compared with polystyrene (PS).The weight loss of PS/Silica microspheres were less than polystyrene (PS) which weightlessness ratio is 96.92 wt %. The compressive strength of PS/Silica microspheres was almost two times as many as pure PS microspheres. The formation mechanism of monodisperse functional PS/Silica microsphere was developed ahead according to the results of FTIR, SEM, EDS and BEI under various polymerization conditions.

Study on CO 2 Adsorption of Sepoilite Modified by Mixture of Ethanolamine and N, N-Dimethyl Ethanolamine

Sepoilite was surface-modified by the mixture of ethanolamine and n, n-dimethyl ethanolamine. The XRD, SEM, FT-IR, BET and TGA were used to characterize the material structure and the adsorption property in CO2. The results showed that the weight percentage of CO2 adsorption rose from 4.01% for pure sepoilite to 19.28% for the modified sepoilite at room temperature.